Facebook ended up paying $715 million to purchase Instagram instead of the original $1 billion figure agreed upon earlier this year, according to a quarterly investment report filed today.

The social network paid $521 million in stocks and cash that was set aside for the purchase, but also added an additional 11 million shares for Instagram employees at the close of the deal in September, according to the filing with the Securities and Exchange Commission

The $521 million includes about 12 million shares of common stock to Instagram's non-employee stockholders and $300 million in cash. The additional 11 million shares have a value of $194 million.